// Below code is originally from mman-win32
//
/*
 * sys/mman.h
 * mman-win32
 */
#include <errno.h>
#include <io.h>
#ifndef FILE_MAP_EXECUTE
#define FILE_MAP_EXECUTE 0x0020
#endif /* FILE_MAP_EXECUTE */
static int __map_mman_error(const uint32_t err, const int deferr) {
  if (err == 0) return 0;
  //TODO: implement
  return err;
}
static uint32_t __map_mmap_prot_page(const int prot) {
  uint32_t protect = 0;
  if (prot == PROT_NONE) return protect;
  if ((prot & PROT_EXEC) != 0) {
    protect =
        ((prot & PROT_WRITE) != 0) ? PAGE_EXECUTE_READWRITE : PAGE_EXECUTE_READ;
  } else {
    protect = ((prot & PROT_WRITE) != 0) ? PAGE_READWRITE : PAGE_READONLY;
  }
  return protect;
}
static uint32_t __map_mmap_prot_file(const int prot) {
  uint32_t desiredAccess = 0;
  if (prot == PROT_NONE) return desiredAccess;
  if ((prot & PROT_READ) != 0) desiredAccess |= FILE_MAP_READ;
  if ((prot & PROT_WRITE) != 0) desiredAccess |= FILE_MAP_WRITE;
  if ((prot & PROT_EXEC) != 0) desiredAccess |= FILE_MAP_EXECUTE;
  return desiredAccess;
}
void *mmap(void *addr, size_t len, int prot, int flags, int fildes,
           ssize_t off) {
  HANDLE fm, h;
  void *map = MAP_FAILED;
#ifdef _MSC_VER
#pragma warning(push)
#pragma warning(disable : 4293)
#endif
  const uint32_t dwFileOffsetLow = (uint32_t) (off & 0xFFFFFFFFL);
  const uint32_t dwFileOffsetHigh = (uint32_t) ((off >> 32) & 0xFFFFFFFFL);
  const uint32_t protect = __map_mmap_prot_page(prot);
  const uint32_t desiredAccess = __map_mmap_prot_file(prot);
  const ssize_t maxSize = off + (ssize_t) len;
  const uint32_t dwMaxSizeLow = (uint32_t) (maxSize & 0xFFFFFFFFL);
  const uint32_t dwMaxSizeHigh = (uint32_t) ((maxSize >> 32) & 0xFFFFFFFFL);
#ifdef _MSC_VER
#pragma warning(pop)
#endif
  errno = 0;
  if (len == 0
      /* Unsupported flag combinations */
      || (flags & MAP_FIXED) != 0
      /* Usupported protection combinations */
      || prot == PROT_EXEC) {
    errno = EINVAL;
    return MAP_FAILED;
  }
  h = ((flags & MAP_ANONYMOUS) == 0) ? (HANDLE) _get_osfhandle(fildes)
                                     : INVALID_HANDLE_VALUE;
  if ((flags & MAP_ANONYMOUS) == 0 && h == INVALID_HANDLE_VALUE) {
    errno = EBADF;
    return MAP_FAILED;
  }
  fm = CreateFileMapping(h, NULL, protect, dwMaxSizeHigh, dwMaxSizeLow, NULL);
  if (fm == NULL) {
    errno = __map_mman_error(GetLastError(), EPERM);
    return MAP_FAILED;
  }
  map =
      MapViewOfFile(fm, desiredAccess, dwFileOffsetHigh, dwFileOffsetLow, len);
  CloseHandle(fm);
  if (map == NULL) {
    errno = __map_mman_error(GetLastError(), EPERM);
    return MAP_FAILED;
  }
  return map;
}
int munmap(void *addr, size_t len) {
  if (UnmapViewOfFile(addr)) return 0;
  errno = __map_mman_error(GetLastError(), EPERM);
  return -1;
}
int mprotect(void *addr, size_t len, int prot) {
  uint32_t newProtect = __map_mmap_prot_page(prot);
  uint32_t oldProtect = 0;
  if (VirtualProtect(addr, len, newProtect, &oldProtect)) return 0;
  errno = __map_mman_error(GetLastError(), EPERM);
  return -1;
}
int msync(void *addr, size_t len, int flags) {
  if (FlushViewOfFile(addr, len)) return 0;
  errno = __map_mman_error(GetLastError(), EPERM);
  return -1;
}
int mlock(const void *addr, size_t len) {
  if (VirtualLock((LPVOID) addr, len)) return 0;
  errno = __map_mman_error(GetLastError(), EPERM);
  return -1;
}
int munlock(const void *addr, size_t len) {
  if (VirtualUnlock((LPVOID) addr, len)) return 0;
  errno = __map_mman_error(GetLastError(), EPERM);
  return -1;
}
